The Welsh side looked set to suffer a similarly large defeat at St Mary's after a woeful first half in which Gaston Ramirez rattled the crossbar.

However, wayward finishing and a fine display from goalkeeper David Marshall kept the hosts at bay, allowing the away side to sneak an improbable win from a surprising source.

Having failed to clear their line, Cala - one of four changes from last weekend's embarrassing loss - showed poise and skill few would expect from a centre-back to strike home from the edge of the box.

Mauricio Pochettino's side pressed for a late leveller but it was not to be as they failed to score for just the sixth time this season, giving Solskjaer's men a huge three points.